Multithread pin insulator assembly



Oct. 19, 1937. c 2,096,613

MULTITHREAD PIN INSULATOR ASSEMBLY Filed April 17, 1956 Invent Gregory C. 'II,

{Q9 gag 7 6 19% Patented Oct. 19, 1937 UNITED STATES PATENT OFFICE Gregory G. Hill, Baltimore, Md., assignor to Locke Insulator Corporation, Baltimore, Md., a corporation of Maryland Application April 17, 1936, Serial No. 74,900

8 Claims.

The present invention relates to supports for pin type insulators. In insulators of this type, it is desirable that the insulator be firmly supported and that the support permit ready alignment of the insulator with a conductor carried by the insulator.

The object of my invention is to provide an improved arrangement for supporting insulators of this type, and for a consideration of what I believe to be novel and my invention, attention is directed to the accompanying description and the claims appended thereto.

In the accompanying drawing, Fig. 1 is a perspective view of a pin type insulator having a support embodying my invention; Fig. 2 is an exploded sectional view of the insulator and the support therefor; Fig. 3 is a sectional view showing the support threaded in place in the insulator; Fig. 4 is a perspective view of the metal cap which connects the insulator to the supporting arm, and Fig. 5 is a sectional view of a modification of my invention.

In the accompanying drawing, there is shown a suitable steel supporting arm I which is attached to a pole 2 and which carries a pin type porcelain insulator 3 having a transverse groove 4 in its top in which a conductor 5 is supported. The conductor is attached to the insulator by a wire 6 which extends beneath a flange 1 on the insulator and is wrapped around the conductor, at each side. The lower end of the insulator is provided with a threaded socket 8 so that the insulator may be threaded on a supporting arm. The threads are formed in the porcelain before firing and during firing are likely to become irregular. The threads are also relatively weak compared to metal.

The supporting arm I is provided with a threaded end 9 on which is threaded a cap H) of lead or other soft metal. The cap [0 is preferably die cast directly on the threaded end 9, thereby eliminating special tools for producing the threads in the cap. While the cap is still in the die, the threaded end 9 of the arm is unthreaded slightly from the cap, for example, a turn and a half. The threads on the arm may be galvanized and may be provided with a coating of oil and graphite, powdered clay, or whiting in order to prevent freezing tightly the cap to the arm due to a soldering or brazing action during the casting. After removal from the die, a longitudinal slit ii may be cut in the cap to decrease the friction between the cap and the arm. This slit is particularly important if the coefficient of expansion of the material of the cap is greater than the coefficient of expansion of the material of the arm.

In the use of the support, the insulator 3 is threaded tightly on the cap ID. The soft metal of the cap prevents breaking of the threads in the socket 8 of the insulator in case of irregularity of these threads, The threads in the socket 8 are preferably arranged so that when the insulator is completely threaded on the cap the cap is spaced from the bottom of the socket i as shown in Figs. 3 and 5. This prevents stress on the bottom of the socket which would tend to break the top of the insulator. When the insulator is threaded on the cap 10 the groove 4 may be out of alignment with the conductor 5 which is to be supported by the insulator. Due to the fragile nature of the insulator, it is not possible to further tighten the insulator on the cap in order to secure the proper alignment. Also it is undesirable that the insulator be loosened on the cap to secure the proper alignment, as this would permit vibration of the insulator on the cap. With the arrangement illustrated, the alignment of the insulator with respect to the conductor may be changed by giving the insulator a sudden twist. This twist will not turn the insulator on the can but will turn the cap on the threaded end of the supporting arm. The space between the end of the arm and the bottom of the cap keeps the arm from striking the bottom of the cap and transferring the force of the sudden twist directly to the insulator. With the construction shown in Figs. 2 and 3 the cap and socket are provided with right hand threads, while the threaded end 9 of the supportmg arm is provided with a left hand thread. After the insulator is threaded on the cap, the insulator is therefore given a sudden twist in a counterclockwise direction. In the construction shown in Fig. 5 all of the threads are right hand threads, so that after the insulator is threaded on the cap the insulator is given a sudden twist in a clockwise direction. With this arrangement, the alignment of the insulator may be changed without breaking the insulator or decreasing the rigidity of the support for the insulator.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A support for a pin type insulator having a threaded socket in one end, comprising an arm having a threaded end, and a cap having internal threads threaded on said arm and having external threads adapted to co-operate with the threads in said socket, said cap being mounted on the arm prior to threading the insulator thereon,

40 I that the cap exerts no pressure on the bottom of the friction between the respective threads being such that when the insulator is threaded on the cap a sudden twist will cause turning of the cap on the arm without'turning of the insulator 'on the cap, thereby changing the aligmnent of the t insulator.

' 2. A support for a pin type insulator having a threaded socket in one end, comprising an arm the alignment of the insulator. V i. In combination, a pintype insulator having having a threaded end, a soft metal cap cast on said threaded end, and external threads on said 7 cap adapted to co-operate with the threads in said socket, said cap being partially unthreaded from said arm prior to threading the insulator thereon, and the friction between the respectivethreads.

being such that when the insulator is threaded on the cap a sudden twist will cause turning of the cap on the'arm, thereby changing the alignment 7 of the insulator.

3. A support for a pin type insulator'having a threaded socket in one end, comprising an arm having a threaded end, a cap of soft metal cast on said threaded end, a longitudinal slot inisaid cap for reducing the pressure between the threads on the arm and the cap, and external threads on said cap :adapted to co-operate with the threads in said socket, said cap being partially unthreaded 'from' said arm prior to threading the insulator thereon, and the friction between the respective threads being such that when the insulator is threaded-on the; cap a. sudden'twist will cause turning of the cap on the arm, thereby changing Va threadedsocket' in one end, asupporting arm having a threaded end, and a cap having internal threads threaded 'on said armand having eX-" ternal'threadsadapted to cc-operate with'the threads in said socket, said cap being mounted on the'arm prior to threading the-insulator thereon, the threads on'the socket'and cap being such said socket when the insulator is threaded on the cap, and the friction between the respective threads being such that. when the insulator is threaded on the cap, a sudden twist will cause turning of the cap on the arm without turning of the insulator on the cap, thereby changing the alignment of the insulator.

, r 5. A'support for a pin type insulator having a threaded socket in one end, comprising an arm having a threaded end, a'soft metal cap cast on said threaded end, a coating on said threaded end for preventing freezing of the cap thereto, and

external threads on said cap adapted'to cooper- I ate with the threads in said socket, said cap being partially unthreaded from said arm' prior to threading the insulator thereon, and the friction between the respective threads being such that when the insulator is threaded on the cap a sudden twist will cause turning'of the cap on the armthereby changing the alignment of the insulator. f U

6. A support for a pin'type insulator having a threaded socket in one end, comprising an arm having a threaded end, and a cap having internal threads threaded on said arm and having external threads adapted to cooperate with the threads in said socket, said cap'beingpartially unthreaded from'said arm prior to threading the insulator thereonpand the friction between the respective threads being such that when the insulator is threaded on the cap a sudden twist will causeturning of the cap' on the arm without turning, of the insulator on the cap, thereby changing the alignment of the insulator. V

'7. A support for apin type insulator having a threaded socket in one end, comprising an arm having 'a threaded end, a cap having internal threads threaded on said arm and having external threads adapted to cooperate with the threads in said socket, and a longitudinal slot in said cap for reducing the pressure between the threads on the. arm, and the cap, said cap'being mounted on the arm prior to threading the insu- 1 latorthereon,.-and the friction between the re-' spective threads being such that when the insu later is threaded on the cap a sudden twist will cause turning of the cap on the'arm. without 7 turning of the insulator on the cap, thereby changing the alignment of the insulator. t

8. In combination a pin type insulator having a threaded socket in one end, a supporting arm having a threaded end, and a cap havinginternal threads threaded on said arm and having external threads adapted to cooperate with the threads in v GREGORY c. HILL; 

